Mechanics of wind erosion-induced dust emission from soil crusts: A theoretical predictive model

Desertification due to wind erosion poses a major threat to global ecosystems, especially in the drying lakes and deserts, where the occurrence of drought events has led to a dramatic increase in crusted surface dust emissions in the region. Soil crusts are a widely occurring surface feature that play a critical role in dust emission when subjected to sand grain impacts. However, existing research lacks a comprehensive model rooted in physical mechanisms, potentially hindering accurate global dust cycle simulations. This paper presents a physical model for analyzing dust emissions from soil crust surfaces under saltation bombardment, and establishes an analytical expression between the rate of wind erosion of crust surfaces and the physicomechanical properties of impacted particles and crusts. This study demonstrated a unique linear relationship between sand particle mass flux and surface crust wind erosion rate, which was verified by field and wind tunnel tests. A sensitivity analysis reveals that the wind erosion rate increases and then decreases with increasing particle size of the impacting particles and crust thickness, with peak erosion occurring, and in addition, crusts with high stiffness and low strength are more likely to be destroyed, with higher surface dust release capacity. The work in this paper fills a gap in the wind erosion parameterization scheme and helps to improve the accuracy of dust release simulation in large and mesoscale models.